A watchdog has called for scandal-hit Wandsworth prison to be put into emergency measures amid concerns over failings in security and severe problems with overcrowding, drugs, violence and self-harm.

Chief inspector of prisons Charlie Taylor wrote to Justice Secretary Alex Chalk to issue an urgent notification for improvement at the category B Victorian jail in south-west London after “deeply concerning” inspection findings.

Mr Taylor – who previously suggested the jail should be closed – told Mr Chalk the prison was “still reeling” from a “very high-profile” alleged escape in September last year.

Daniel Khalife is accused of fleeing custody while being held on remand over spy charges. He allegedly strapped himself underneath a food delivery lorry and was arrested a few days later. The former soldier denies all the charges against him and is due to stand trial in October.

Security remained a “serious concern” at the prison, with “chaotic” wings and staff across most units unable to “accurately account for their prisoners during the working day”, Mr Taylor warned as he described it as “unfathomable” that bosses had “not focused their attention on this area”.

The Prison Governors’ Association (PGA) said the move “will be of no surprise to the Government”, in the wake of the prison’s boss Katie Price resigning during the inspection.

Mr Taylor said: “The poor outcomes we found at Wandsworth are systemic and cultural failures and stemmed from poor leadership at every level of the prison, from HMPPS (His Majesty’s Prison and Probation Service) and the Ministry of Justice.”

Many “well-meaning and hard-working leaders and staff persevered” but they were often “fighting against a tide of cross-cutting, intractable problems that require comprehensive, long-term solutions”.

The “troubled prison” needs “permanent experienced leaders at all levels” to begin to recover, he said, warning: “Until this happens, the risk of a further catastrophe, a self-inflicted death or escape from lawful custody, is ever present.”

The PGA said staff at the jail were in an “almost impossible situation”, the governor at Wandsworth “decided to leave” earlier this year and “resigned during the inspection”, adding that this was “undoubtedly due in part to the personal toll that running a prison like Wandsworth in current times takes”.

The prison was “not reducing the risk of men reoffending”, the watchdog’s inspection carried out between April 22 and May 2 found.

Relationships between staff and prisoners were “poor or non-existent”.

Most staff at every level were “very inexperienced”, and, despite being fully staffed “on paper”, more than a third of staff were not available for work each day, leading to additional restrictions on prisoners and “burnt-out prison officers struggling to keep things going”.

Inspectors highlighted how some staff “did not understand their role and they lacked direction, training, and consistent support from leaders, many of whom were themselves inexperienced and temporarily promoted”.

Seven prisoners had taken their own lives in the past year, Mr Taylor said.

Some 80% of the 1,513 men held there were sharing cells designed for one person and most inmates spent more than 22 hours confined to the “cramped, squalid” conditions with “no idea if or when they would leave them or have any access to fresh air”, according to the findings.

Many inmates were “in despair”, he said as he highlighted how prisoners on one wing had not been able to shower for five days.

Self-harm was high, with inspectors finding men “in clear distress and without support” and 40% of emergency cell bells not being answered within the required five minutes.

Pia Sinha, chief executive of the Prison Reform Trust, said the “damning” findings reveal a “failure of leadership from top to bottom”, adding: “Ministers cannot be exempt from the criticism levelled against the prison by the chief inspector.”

Prisons minister Edward Argar said the “deeply concerning report” shows the jail continues to face “significant challenges” and it was “clear that on top of the additional support we’ve already provided since September to improve safety and security, including nearly £1 million of upgrades, we need to go further still.”

Extra experienced staff will be added to the prison’s management team in the coming weeks to provide the “leadership, culture change and training needed to turn Wandsworth around”, he said, adding: “In the interim we are deploying more staff, including prison officers, to the prison and will set out further action shortly.”

Wandsworth is the sixth prison to be issued with an urgent notification since November 2022, joining Exeter, Woodhill, Bristol and Bedford jails as well as Cookham Wood young offender institution.

The notice effectively places the jail in special measures and means the Justice Secretary has to urgently produce an action plan for improvement before the watchdog carries out another inspection.

The full findings of the latest inspection which prompted the urgent notification will be published at a later date.